3 Answers
3

If your wallet has a Bitcoin Cash version of it (e.g. Bitcoin ABC for Bitcoin Core, Electron Cash for Electrum), then you can install that version in a second location and have it use a different data directory (the data for wallets is stored separately from the install location). Then just copy your wallet file into the second data directory and use the Bitcoin Cash version of your wallet as you normally would use your wallet. Since Bitcoin Cash has implemented two way replay protection, there isn't anything special that you need to do in order to properly create transactions for either chain.

If you do not have a wallet that has a Bitcoin Cash counterpart, you can export your private key(s) and import it into a Bitcoin Cash wallet. After the fork, you should first send your Bitcoin to another address that you control. Then you can export your private keys (excluding the private key for the address you just sent Bitcoin to) and import then into a Bitcoin Cash wallet. From there you can send your Bitcoin Cash coins to an address in the Bitcoin Cash wallet and spend normally.

NOTICE: Make sure to always backup your wallet.dat. I've heard of horror stories about people downloading bitcoinabc client and it overwrites their current bitcoin files. It's best to use a extra computer to download bitcoinabc and then use email or a USB to transfer wallet.dat to it.

Since you hold the private key of your wallet, you just need to import it to a BCC wallet after the fork and you will get access to your bitcoin cash,

After 12:20 UTC (or maybe you need to wait for 1 BCC block?), send all of your BTC to a totally new wallet and wait until this gets 30 confirmations. Just creating new addresses is not sufficient: you must create a totally new wallet file with a different mnemonic, etc. BCC has some replay protection (note: contrary to what they say, it is not complete replay protection, unless they changed it since I last heard), so this should typically not be replayed. Just in case it is replayed, the destination wallet should also be under your complete control.

Import your old private keys into a BCC wallet on a separate computer, or upload them to a BCC exchange/bank. Never use that wallet file again.

I've sent my BTC to a new address, then imported the private key to BCH wallet from my previous BTC address. In the BCH wallet, I see the same transaction done, and thus there 0 BCH balance. How do I get my BCH in this case?
– siamiiAug 1 '17 at 23:32

@siamii: you did this too early, before the split! You should do the same again, send it to into a new wallet and watch your second wallet in your BCH Wallet
– rubo77Aug 2 '17 at 11:15